During my 5,000 mile service visit the dealer did a CPU update. Following that. my mileage dropped from 49 mpg average to 47 mpg average. During my 10,000 mile service visit the dealer did another CPU update. Following that, my mileage increased from 47 mpg to 50 mpg. I can't see any factor other than the CPU update that might have affected mileage. In both cases, I checked the tire pressure following each visit. In both cases the tire pressure was factory spec. Anyone else experience this?
What kind of CPU "updates" were done and why? Many Prius owners, myself included, have stated that they notice a mileage change when the oil level is too high. The oil should be somewhere between full and low, not at or above full.
